• ANS & adrenoceptors
• The autonomic nervous system
• Sympathetic nervous system (SNS)
• Thoracolumbar outflow (T1-L2)
• Parasympathetic nervous system (PSNS)
• Craniosacral outflow
• Cranial nerves III, VII, IX, X & S2-4
• SNS & PSNS pre-ganglionic fibres are β fibres and release ACh
• Post-ganglionic fibres (C fibres)
• SNS
• Release NA which binds to adrenoceptors
• Adrenals secrete adrenaline
• Sweat glands are ACh mediated
• PSNS
• ACh released which bind to muscarinic receptors
• Adrenoceptors
• G-protein coupled receptors
  Link:Receptors
  
• Found on post-synaptic membranes of end organs; uterus, liver, heart, lungs, vasculature
• Receptor
• Effects of stimulation
• α1 (Gq)
• Vasoconstriction, relaxation of GI tract, saliva secretion
• α2 (Gi)
• Platelet aggregation
• β1 (Gs)
• Positive inotropy/chonotropy, lipolysis, relaxes GI smooth muscle
• β2 (Gs)
• Bronchodilatation, uterine relaxation, dilates muscle vascular
• β3 (Gs)
• Lipolysis (brown fat)
• Sympatomimetics (NAMED PC SIDD)
• Natural
• Adrenaline, NA, dopamine
• Synthetic
• Isoprenaline, ephedrine, dopexamine, metaraminol, phenylephrine
• Drug
• α1
• α2
• β1
• β2
• Dopamine
• Noradr
• ++++
• O
• ++
• ++
• Dose dependent
• Adren
• +++
• O
• ++
• ++
• O
• Metaraminol
• ++
• O
• +
• +
• O
• Ephedrine
• +
• O
• ++
• ++
• O
• Dopamine
• +
• O
• +
• +
• ++ (low dose stimulates DA only)
• Phenyleph
• +++
• O
• O
• O
• O
• Clonidine
• O
• ++
• O
• O
• O
• Salbutamol
• O
• O
• +
• ++
• O
• Isoprenaline
• 0
• O
• ++
• ++
• O
• Dobutamine
• O
• O
• ++
• +
• O
• Dopexamine
• O
• O
• +
• ++
• O